Debugging code: comment or remove?

How do the Nitpickers feel about debugging code: should I excise it from my code before submission to the Nitpickers, or can I leave it in, commented? Frexample, I'm doing 1b Hundred.java, and for debugging I print an 80-char 'scale'. I'd like to leave that code in as comments so I can save it later, without the joy of saving two versions of the same exercise. But of course I'll whack it if the nitpickers say so.